Abstract Orthorhombic molybdenum trioxide (α-MoO3) nanofibers with controlled morphology and diameter were synthesized by adjusting electrospinning and calcination conditions. Experimental design was utilized to vary several factors including solution properties, electrospinning parameters and environmental conditions to analyze their effects toward nanofiber morphology (i.e., diameter and bead density). Polyvinylpyrrolidone (PVP) content, which effects viscosity, predominated control morphology of nanofibers where low PVP content (i.e., 3.0 wt.%) yielded heavily beaded nanofibers with smaller diameter. The morphology of nanofibers was also tuned by adjusting electrospinning parameters (i.e., applied voltage and feed rate), where smallest nanofibers with minimum bead density was achieved at applied voltage of 8 kV with feed rate of 0.5 mL/h. The as-electrospun ammonium molybdate/polyvinylpyrrolidone nanofibers were calcined to α-MoO3 nanofibers in air. The ramping rate significantly altered the morphology of α-MoO3 nanofibers where rapid thermal annealing with the ramping rate of 15 °C/s yielded smoother nanofibers whereas slower ramping rate yielded platelet-like structures. BET analysis showed an increase in specific surface area with decreasing average diameter (i.e., 6.7 m2/g for 125 nm–86.4 m2/g for 35 nm).

中文翻译：

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具有可控形貌和直径的正交-MoO 3 纳米纤维的合成和表征

摘要 通过调节静电纺丝和煅烧条件，合成了形貌和直径可控的正交三氧化钼（α-MoO3）纳米纤维。实验设计被用来改变几个因素，包括溶液特性、静电纺丝参数和环境条件，以分析它们对纳米纤维形态（即直径和珠密度）的影响。聚乙烯吡咯烷酮 (PVP) 含量影响粘度，控制纳米纤维的形态，其中低 PVP 含量（即 3.0 wt.%）产生具有较小直径的大量珠状纳米纤维。纳米纤维的形态也通过调整静电纺丝参数（即施加的电压和进料速率）进行调整，其中在 8 kV 的施加电压和 0.5 mL/h 的进料速率下实现了具有最小珠密度的最小纳米纤维。将电纺钼酸铵/聚乙烯吡咯烷酮纳米纤维在空气中煅烧成 α-MoO3 纳米纤维。升温速率显着改变了 α-MoO3 纳米纤维的形态，其中升温速率为 15°C/s 的快速热退火产生更光滑的纳米纤维，而较慢的升温速率产生片状结构。BET 分析显示比表面积随着平均直径的减小而增加（即，125 nm 为 6.7 m2/g–35 nm 为 86.4 m2/g）。